Kernel/arch/x86/mm_virt.c

   1 /*
   2  * AcessOS Microkernel Version
   3  * mm_virt.c
   4  *
   5  * Memory Map
   6  * 0xE0 - Kernel Base
   7  * 0xF0 - Kernel Stacks
   8  * 0xFD - Fractals
   9  * 0xFE - Unused
  10  * 0xFF - System Calls / Kernel's User Code
  11  */
  12 #include <common.h>
  13 #include <mm_phys.h>
  14 #include <proc.h>
  15
  16 #define KERNEL_STACKS   0xF0000000
  17 #define KERNEL_STACK_SIZE       0x00002000
  18 #define KERNEL_STACK_END        0xFD000000
  19 #define PAGE_TABLE_ADDR 0xFD000000
  20 #define PAGE_DIR_ADDR   0xFD3F4000
  21 #define PAGE_CR3_ADDR   0xFD3F4FD0
  22 #define TMP_CR3_ADDR    0xFD3F4FD4      // Part of core instead of temp
  23 #define TMP_DIR_ADDR    0xFD3F5000      // Same
  24 #define TMP_TABLE_ADDR  0xFD400000
  25 #define HW_MAP_ADDR             0xFD800000
  26 #define HW_MAP_MAX              0xFEFF0000
  27 #define NUM_HW_PAGES    ((HW_MAP_MAX-HW_MAP_ADDR)/0x1000)
  28 #define TEMP_MAP_ADDR   0xFEFF0000      // Allows 16 "temp" pages
  29 #define NUM_TEMP_PAGES  16
  30
  31 #define PF_PRESENT      0x1
  32 #define PF_WRITE        0x2
  33 #define PF_USER         0x4
  34 #define PF_COW          0x200
  35 #define PF_PAGED        0x400
  36
  37 #define INVLPG(addr)    __asm__ __volatile__ ("invlpg (%0)"::"r"(addr))
  38
  39 // === IMPORTS ===
  40 extern Uint32   gaInitPageDir[1024];
  41 extern Uint32   gaInitPageTable[1024];
  42
  43 // === PROTOTYPES ===
  44 void    MM_PreinitVirtual();
  45 void    MM_InstallVirtual();
  46 void    MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs);
  47 void    MM_DumpTables(tVAddr Start, tVAddr End);
  48 tPAddr  MM_DuplicatePage(Uint VAddr);
  49
  50 // === GLOBALS ===
  51 tPAddr  *gaPageTable = (void*)PAGE_TABLE_ADDR;
  52 tPAddr  *gaPageDir = (void*)PAGE_DIR_ADDR;
  53 tPAddr  *gaPageCR3 = (void*)PAGE_CR3_ADDR;
  54 tPAddr  *gaTmpTable = (void*)TMP_TABLE_ADDR;
  55 tPAddr  *gaTmpDir = (void*)TMP_DIR_ADDR;
  56 tPAddr  *gTmpCR3 = (void*)TMP_CR3_ADDR;
  57  int    gilTempMappings = 0;
  58
  59 // === CODE ===
  60 /**
  61  * \fn void MM_PreinitVirtual()
  62  * \brief Maps the fractal mappings
  63  */
  64 void MM_PreinitVirtual()
  65 {
  66         gaInitPageDir[ 0 ] = 0;
  67         gaInitPageDir[ PAGE_TABLE_ADDR >> 22 ] = ((Uint)&gaInitPageDir - KERNEL_BASE) | 3;
  68 }
  69
  70 /**
  71  * \fn void MM_InstallVirtual()
  72  * \brief Sets up the constant page mappings
  73  */
  74 void MM_InstallVirtual()
  75 {
  76          int    i;
  77
  78         // --- Pre-Allocate kernel tables
  79         for( i = KERNEL_BASE>>22; i < 1024; i ++ )
  80         {
  81                 if( gaPageDir[ i ] )    continue;
  82                 // Skip stack tables, they are process unique
  83                 if( i > KERNEL_STACKS >> 22 && i < KERNEL_STACK_END >> 22) {
  84                         gaPageDir[ i ] = 0;
  85                         continue;
  86                 }
  87                 // Preallocate table
  88                 gaPageDir[ i ] = MM_AllocPhys() | 3;
  89                 INVLPG( &gaPageTable[i*1024] );
  90                 memset( &gaPageTable[i*1024], 0, 0x1000 );
  91         }
  92 }
  93
  94 /**
  95  * \fn void MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs)
  96  * \brief Called on a page fault
  97  */
  98 void MM_PageFault(Uint Addr, Uint ErrorCode, tRegs *Regs)
  99 {
 100         //ENTER("xAddr bErrorCode", Addr, ErrorCode);
 101
 102         // -- Check for COW --
 103         if( gaPageDir  [Addr>>22] & PF_PRESENT
 104          && gaPageTable[Addr>>12] & PF_PRESENT
 105          && gaPageTable[Addr>>12] & PF_COW )
 106         {
 107                 tPAddr  paddr;
 108                 if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
 109                 {
 110                         gaPageTable[Addr>>12] &= ~PF_COW;
 111                         gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
 112                 }
 113                 else
 114                 {
 115                         paddr = MM_DuplicatePage( Addr );
 116                         MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
 117                         gaPageTable[Addr>>12] &= PF_USER;
 118                         gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
 119                 }
 120                 LOG("Duplicated page at %p to 0x%x", Addr&~0xFFF, gaPageTable[Addr>>12]);
 121                 INVLPG( Addr & ~0xFFF );
 122                 //LEAVE('-')
 123                 return;
 124         }
 125
 126         // -- Check Error Code --
 127         if(ErrorCode & 8)
 128                 Warning("Reserved Bits Trashed!");
 129         else
 130         {
 131                 Warning("%s %s %s memory%s",
 132                         (ErrorCode&4?"User":"Kernel"),
 133                         (ErrorCode&2?"write to":"read from"),
 134                         (ErrorCode&1?"bad/locked":"non-present"),
 135                         (ErrorCode&16?" (Instruction Fetch)":"")
 136                         );
 137         }
 138
 139         Log("gaPageDir[0x%x] = 0x%x", Addr>>22, gaPageDir[Addr>>22]);
 140         if( gaPageDir[Addr>>22] & PF_PRESENT )
 141                 Log("gaPageTable[0x%x] = 0x%x", Addr>>12, gaPageTable[Addr>>12]);
 142
 143         MM_DumpTables(0, -1);
 144
 145         Panic("Page Fault at 0x%x\n", Regs->eip);
 146 }
 147
 148 /**
 149  * \fn void MM_DumpTables(Uint Start, Uint End)
 150  * \brief Dumps the layout of the page tables
 151  */
 152 void MM_DumpTables(tVAddr Start, tVAddr End)
 153 {
 154         tVAddr  rangeStart = 0;
 155         tPAddr  expected = 0;
 156         tVAddr  curPos;
 157         Uint    page;
 158         const tPAddr    MASK = ~0xF98;
 159
 160         Start >>= 12;   End >>= 12;
 161         for(page = Start, curPos = Start<<12;
 162                 page < End;
 163                 curPos += 0x1000, page++)
 164         {
 165                 if( !(gaPageDir[curPos>>22] & PF_PRESENT)
 166                 ||  !(gaPageTable[page] & PF_PRESENT)
 167                 ||  (gaPageTable[page] & MASK) != expected)
 168                 {
 169                         if(expected) {
 170                                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 171                                         rangeStart, curPos - 1,
 172                                         gaPageTable[rangeStart>>12] & ~0xFFF,
 173                                         (expected & ~0xFFF) - 1,
 174                                         (expected & PF_PAGED ? "p" : "-"),
 175                                         (expected & PF_COW ? "C" : "-"),
 176                                         (expected & PF_USER ? "U" : "-"),
 177                                         (expected & PF_WRITE ? "W" : "-")
 178                                         );
 179                                 expected = 0;
 180                         }
 181                         if( !(gaPageDir[curPos>>22] & PF_PRESENT) )     continue;
 182                         if( !(gaPageTable[curPos>>12] & PF_PRESENT) )   continue;
 183
 184                         expected = (gaPageTable[page] & MASK);
 185                         rangeStart = curPos;
 186                 }
 187                 if(expected)    expected += 0x1000;
 188         }
 189
 190         if(expected) {
 191                 Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
 192                         rangeStart, curPos - 1,
 193                         gaPageTable[rangeStart>>12] & ~0xFFF,
 194                         (expected & ~0xFFF) - 1,
 195                         (expected & PF_PAGED ? "p" : "-"),
 196                         (expected & PF_COW ? "C" : "-"),
 197                         (expected & PF_USER ? "U" : "-"),
 198                         (expected & PF_WRITE ? "W" : "-")
 199                         );
 200                 expected = 0;
 201         }
 202 }
 203
 204 /**
 205  * \fn tPAddr MM_Allocate(Uint VAddr)
 206  */
 207 tPAddr MM_Allocate(Uint VAddr)
 208 {
 209         tPAddr  paddr;
 210         // Check if the directory is mapped
 211         if( gaPageDir[ VAddr >> 22 ] == 0 )
 212         {
 213                 // Allocate directory
 214                 paddr = MM_AllocPhys();
 215                 if( paddr == 0 ) {
 216                         Warning("MM_Allocate - Out of Memory (Called by %p)", __builtin_return_address(0));
 217                         return 0;
 218                 }
 219                 // Map
 220                 gaPageDir[ VAddr >> 22 ] = paddr | 3;
 221                 // Mark as user
 222                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 223
 224                 INVLPG( &gaPageDir[ VAddr >> 22 ] );
 225                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 226         }
 227         // Check if the page is already allocated
 228         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 229                 Warning("MM_Allocate - Allocating to used address (%p)", VAddr);
 230                 return gaPageTable[ VAddr >> 12 ] & ~0xFFF;
 231         }
 232
 233         // Allocate
 234         paddr = MM_AllocPhys();
 235         if( paddr == 0 ) {
 236                 Warning("MM_Allocate - Out of Memory when allocating at %p (Called by %p)",
 237                         VAddr, __builtin_return_address(0));
 238                 return 0;
 239         }
 240         // Map
 241         gaPageTable[ VAddr >> 12 ] = paddr | 3;
 242         // Mark as user
 243         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 244         // Invalidate Cache for address
 245         INVLPG( VAddr & ~0xFFF );
 246
 247         return paddr;
 248 }
 249
 250 /**
 251  * \fn void MM_Deallocate(Uint VAddr)
 252  */
 253 void MM_Deallocate(Uint VAddr)
 254 {
 255         if( gaPageDir[ VAddr >> 22 ] == 0 ) {
 256                 Warning("MM_Deallocate - Directory not mapped");
 257                 return;
 258         }
 259
 260         if(gaPageTable[ VAddr >> 12 ] == 0) {
 261                 Warning("MM_Deallocate - Page is not allocated");
 262                 return;
 263         }
 264
 265         // Dereference page
 266         MM_DerefPhys( gaPageTable[ VAddr >> 12 ] & ~0xFFF );
 267         // Clear page
 268         gaPageTable[ VAddr >> 12 ] = 0;
 269 }
 270
 271 /**
 272  * \fn tPAddr MM_GetPhysAddr(Uint Addr)
 273  * \brief Checks if the passed address is accesable
 274  */
 275 tPAddr MM_GetPhysAddr(Uint Addr)
 276 {
 277         if( !(gaPageDir[Addr >> 22] & 1) )
 278                 return 0;
 279         if( !(gaPageTable[Addr >> 12] & 1) )
 280                 return 0;
 281         return (gaPageTable[Addr >> 12] & ~0xFFF) | (Addr & 0xFFF);
 282 }
 283
 284 /**
 285  * \fn void MM_SetCR3(Uint CR3)
 286  * \brief Sets the current process space
 287  */
 288 void MM_SetCR3(Uint CR3)
 289 {
 290         __asm__ __volatile__ ("mov %0, %%cr3"::"r"(CR3));
 291 }
 292
 293 /**
 294  * \fn int MM_Map(Uint VAddr, tPAddr PAddr)
 295  * \brief Map a physical page to a virtual one
 296  */
 297 int MM_Map(Uint VAddr, tPAddr PAddr)
 298 {
 299         //ENTER("xVAddr xPAddr", VAddr, PAddr);
 300         // Sanity check
 301         if( PAddr & 0xFFF || VAddr & 0xFFF ) {
 302                 Warning("MM_Map - Physical or Virtual Addresses are not aligned");
 303                 //LEAVE('i', 0);
 304                 return 0;
 305         }
 306
 307         // Align addresses
 308         PAddr &= ~0xFFF;        VAddr &= ~0xFFF;
 309
 310         // Check if the directory is mapped
 311         if( gaPageDir[ VAddr >> 22 ] == 0 )
 312         {
 313                 gaPageDir[ VAddr >> 22 ] = MM_AllocPhys() | 3;
 314
 315                 // Mark as user
 316                 if(VAddr < MM_USER_MAX) gaPageDir[ VAddr >> 22 ] |= PF_USER;
 317
 318                 INVLPG( &gaPageTable[ (VAddr >> 12) & ~0x3FF ] );
 319                 memsetd( &gaPageTable[ (VAddr >> 12) & ~0x3FF ], 0, 1024 );
 320         }
 321         // Check if the page is already allocated
 322         else if( gaPageTable[ VAddr >> 12 ] != 0 ) {
 323                 Warning("MM_Map - Allocating to used address");
 324                 //LEAVE('i', 0);
 325                 return 0;
 326         }
 327
 328         // Map
 329         gaPageTable[ VAddr >> 12 ] = PAddr | 3;
 330         // Mark as user
 331         if(VAddr < MM_USER_MAX) gaPageTable[ VAddr >> 12 ] |= PF_USER;
 332
 333         //LOG("gaPageTable[ 0x%x ] = (Uint)%p = 0x%x",
 334         //      VAddr >> 12, &gaPageTable[ VAddr >> 12 ], gaPageTable[ VAddr >> 12 ]);
 335
 336         // Reference
 337         MM_RefPhys( PAddr );
 338
 339         //LOG("INVLPG( 0x%x )", VAddr);
 340         INVLPG( VAddr );
 341
 342         //LEAVE('i', 1);
 343         return 1;
 344 }
 345
 346 /**
 347  * \fn Uint MM_ClearUser()
 348  * \brief Clear user's address space
 349  */
 350 Uint MM_ClearUser()
 351 {
 352         Uint    i, j;
 353
 354         // Copy Directories
 355         for( i = 0; i < (MM_USER_MAX>>22); i ++ )
 356         {
 357                 // Check if directory is not allocated
 358                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 359                         gaPageDir[i] = 0;
 360                         continue;
 361                 }
 362
 363
 364                 for( j = 0; j < 1024; j ++ )
 365                 {
 366                         if( gaPageTable[i*1024+j] & 1 )
 367                                 MM_DerefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 368                         gaPageTable[i*1024+j] = 0;
 369                 }
 370
 371                 MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 372         }
 373
 374
 375         return *gTmpCR3;
 376 }
 377
 378 /**
 379  * \fn Uint MM_Clone()
 380  * \brief Clone the current address space
 381  */
 382 Uint MM_Clone()
 383 {
 384         Uint    i, j;
 385         Uint    kStackBase = Proc_GetCurThread()->KernelStack - KERNEL_STACK_SIZE;
 386         void    *tmp;
 387
 388         //ENTER("");
 389
 390         // Create Directory Table
 391         *gTmpCR3 = MM_AllocPhys() | 3;
 392         INVLPG( gaTmpDir );
 393         //LOG("Allocated Directory (%x)", *gTmpCR3);
 394         memsetd( gaTmpDir, 0, 1024 );
 395
 396         // Copy Tables
 397         for(i=0;i<768;i++)
 398         {
 399                 // Check if table is allocated
 400                 if( !(gaPageDir[i] & PF_PRESENT) ) {
 401                         gaTmpDir[i] = 0;
 402                         continue;
 403                 }
 404
 405                 // Allocate new table
 406                 gaTmpDir[i] = MM_AllocPhys() | (gaPageDir[i] & 7);
 407                 INVLPG( &gaTmpTable[i*1024] );
 408                 // Fill
 409                 for( j = 0; j < 1024; j ++ )
 410                 {
 411                         if( !(gaPageTable[i*1024+j] & PF_PRESENT) ) {
 412                                 gaTmpTable[i*1024+j] = 0;
 413                                 continue;
 414                         }
 415
 416                         // Refrence old page
 417                         MM_RefPhys( gaPageTable[i*1024+j] & ~0xFFF );
 418                         // Add to new table
 419                         if(gaPageTable[i*1024+j] & PF_WRITE) {
 420                                 gaTmpTable[i*1024+j] = (gaPageTable[i*1024+j] & ~PF_WRITE) | PF_COW;
 421                                 gaPageTable[i*1024+j] = (gaPageTable[i*1024+j] & ~PF_WRITE) | PF_COW;
 422                         }
 423                         else
 424                                 gaTmpTable[i*1024+j] = gaPageTable[i*1024+j];
 425                 }
 426         }
 427
 428         // Map in kernel tables (and make fractal mapping)
 429         for( i = 768; i < 1024; i ++ )
 430         {
 431                 // Fractal
 432                 if( i == (PAGE_TABLE_ADDR >> 22) ) {
 433                         gaTmpDir[ PAGE_TABLE_ADDR >> 22 ] = *gTmpCR3;
 434                         continue;
 435                 }
 436
 437                 if( gaPageDir[i] == 0 ) {
 438                         gaTmpDir[i] = 0;
 439                         continue;
 440                 }
 441
 442                 //LOG("gaPageDir[%x/4] = 0x%x", i*4, gaPageDir[i]);
 443                 MM_RefPhys( gaPageDir[i] & ~0xFFF );
 444                 gaTmpDir[i] = gaPageDir[i];
 445         }
 446
 447         // Allocate kernel stack
 448         for(i = KERNEL_STACKS >> 22;
 449                 i < KERNEL_STACK_END >> 22;
 450                 i ++ )
 451         {
 452                 // Check if directory is allocated
 453                 if( (gaPageDir[i] & 1) == 0 ) {
 454                         gaTmpDir[i] = 0;
 455                         continue;
 456                 }
 457
 458                 // We don't care about other kernel stacks, just the current one
 459                 if( i != kStackBase >> 22 ) {
 460                         MM_DerefPhys( gaPageDir[i] & ~0xFFF );
 461                         gaTmpDir[i] = 0;
 462                         continue;
 463                 }
 464
 465                 // Create a copy
 466                 gaTmpDir[i] = MM_AllocPhys() | 3;
 467                 INVLPG( &gaTmpTable[i*1024] );
 468                 for( j = 0; j < 1024; j ++ )
 469                 {
 470                         // Is the page allocated? If not, skip
 471                         if( !(gaPageTable[i*1024+j] & 1) ) {
 472                                 gaTmpTable[i*1024+j] = 0;
 473                                 continue;
 474                         }
 475
 476                         // We don't care about other kernel stacks
 477                         if( ((i*1024+j)*4096 & ~(KERNEL_STACK_SIZE-1)) != kStackBase ) {
 478                                 gaTmpTable[i*1024+j] = 0;
 479                                 continue;
 480                         }
 481
 482                         // Allocate page
 483                         gaTmpTable[i*1024+j] = MM_AllocPhys() | 3;
 484
 485                         MM_RefPhys( gaTmpTable[i*1024+j] & ~0xFFF );
 486
 487                         tmp = (void *) MM_MapTemp( gaTmpTable[i*1024+j] & ~0xFFF );
 488                         memcpy( tmp, (void *)( (i*1024+j)*0x1000 ), 0x1000 );
 489                         MM_FreeTemp( (Uint)tmp );
 490                 }
 491         }
 492
 493         //LEAVE('x', *gTmpCR3 & ~0xFFF);
 494         return *gTmpCR3 & ~0xFFF;
 495 }
 496
 497 /**
 498  * \fn Uint MM_NewKStack()
 499  * \brief Create a new kernel stack
 500  */
 501 Uint MM_NewKStack()
 502 {
 503         Uint    base = KERNEL_STACKS;
 504         Uint    i;
 505         for(;base<KERNEL_STACK_END;base+=KERNEL_STACK_SIZE)
 506         {
 507                 if(MM_GetPhysAddr(base) != 0)   continue;
 508                 for(i=0;i<KERNEL_STACK_SIZE;i+=0x1000) {
 509                         MM_Allocate(base+i);
 510                 }
 511                 return base+KERNEL_STACK_SIZE;
 512         }
 513         Warning("MM_NewKStack - No address space left\n");
 514         return 0;
 515 }
 516
 517 /**
 518  * \fn void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 519  * \brief Sets the flags on a page
 520  */
 521 void MM_SetFlags(Uint VAddr, Uint Flags, Uint Mask)
 522 {
 523         tPAddr  *ent;
 524         if( !(gaPageDir[VAddr >> 22] & 1) )     return ;
 525         if( !(gaPageTable[VAddr >> 12] & 1) )   return ;
 526
 527         ent = &gaPageTable[VAddr >> 12];
 528
 529         // Read-Only
 530         if( Mask & MM_PFLAG_RO )
 531         {
 532                 if( Flags & MM_PFLAG_RO )       *ent &= ~PF_WRITE;
 533                 else    *ent |= PF_WRITE;
 534         }
 535
 536         // Kernel
 537         if( Mask & MM_PFLAG_KERNEL )
 538         {
 539                 if( Flags & MM_PFLAG_KERNEL )   *ent &= ~PF_USER;
 540                 else    *ent |= PF_USER;
 541         }
 542
 543         // Copy-On-Write
 544         if( Mask & MM_PFLAG_COW )
 545         {
 546                 if( Flags & MM_PFLAG_COW ) {
 547                         *ent &= ~PF_WRITE;
 548                         *ent |= PF_COW;
 549                 }
 550                 else {
 551                         *ent &= ~PF_COW;
 552                         *ent |= PF_WRITE;
 553                 }
 554         }
 555 }
 556
 557 /**
 558  * \fn tPAddr MM_DuplicatePage(Uint VAddr)
 559  * \brief Duplicates a virtual page to a physical one
 560  */
 561 tPAddr MM_DuplicatePage(Uint VAddr)
 562 {
 563         tPAddr  ret;
 564         Uint    temp;
 565          int    wasRO = 0;
 566
 567         // Check if mapped
 568         if( !(gaPageDir  [VAddr >> 22] & PF_PRESENT) )  return 0;
 569         if( !(gaPageTable[VAddr >> 12] & PF_PRESENT) )  return 0;
 570
 571         // Page Align
 572         VAddr &= ~0xFFF;
 573
 574         // Allocate new page
 575         ret = MM_AllocPhys();
 576
 577         // Write-lock the page (to keep data constistent), saving its R/W state
 578         wasRO = (gaPageTable[VAddr >> 12] & PF_WRITE ? 0 : 1);
 579         gaPageTable[VAddr >> 12] &= ~PF_WRITE;
 580         INVLPG( VAddr );
 581
 582         // Copy Data
 583         temp = MM_MapTemp(ret);
 584         memcpy( (void*)temp, (void*)VAddr, 0x1000 );
 585         MM_FreeTemp(temp);
 586
 587         // Restore Writeable status
 588         if(!wasRO)      gaPageTable[VAddr >> 12] |= PF_WRITE;
 589         INVLPG(VAddr);
 590
 591         return ret;
 592 }
 593
 594 /**
 595  * \fn Uint MM_MapTemp(tPAddr PAddr)
 596  * \brief Create a temporary memory mapping
 597  * \todo Show Luigi Barone (C Lecturer) and see what he thinks
 598  */
 599 Uint MM_MapTemp(tPAddr PAddr)
 600 {
 601          int    i;
 602
 603         //ENTER("XPAddr", PAddr);
 604
 605         PAddr &= ~0xFFF;
 606
 607         //LOG("gilTempMappings = %i", gilTempMappings);
 608
 609         for(;;)
 610         {
 611                 LOCK( &gilTempMappings );
 612
 613                 for( i = 0; i < NUM_TEMP_PAGES; i ++ )
 614                 {
 615                         // Check if page used
 616                         if(gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] & 1)        continue;
 617                         // Mark as used
 618                         gaPageTable[ (TEMP_MAP_ADDR >> 12) + i ] = PAddr | 3;
 619                         INVLPG( TEMP_MAP_ADDR + (i << 12) );
 620                         //LEAVE('p', TEMP_MAP_ADDR + (i << 12));
 621                         RELEASE( &gilTempMappings );
 622                         return TEMP_MAP_ADDR + (i << 12);
 623                 }
 624                 RELEASE( &gilTempMappings );
 625                 Threads_Yield();
 626         }
 627 }
 628
 629 /**
 630  * \fn void MM_FreeTemp(Uint PAddr)
 631  * \brief Free's a temp mapping
 632  */
 633 void MM_FreeTemp(Uint VAddr)
 634 {
 635          int    i = VAddr >> 12;
 636         //ENTER("xVAddr", VAddr);
 637
 638         if(i >= (TEMP_MAP_ADDR >> 12))
 639                 gaPageTable[ i ] = 0;
 640
 641         //LEAVE('-');
 642 }
 643
 644 /**
 645  * \fn Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 646  * \brief Allocates a contigous number of pages
 647  */
 648 Uint MM_MapHWPage(tPAddr PAddr, Uint Number)
 649 {
 650          int    i, j;
 651
 652         PAddr &= ~0xFFF;
 653
 654         // Scan List
 655         for( i = 0; i < NUM_HW_PAGES; i ++ )
 656         {
 657                 // Check if addr used
 658                 if( gaPageTable[ (HW_MAP_ADDR >> 12) + i ] & 1 )
 659                         continue;
 660
 661                 // Check possible region
 662                 for( j = 0; j < Number && i + j < NUM_HW_PAGES; j ++ )
 663                 {
 664                         // If there is an allocated page in the region we are testing, break
 665                         if( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] & 1 )    break;
 666                 }
 667                 // Is it all free?
 668                 if( j == Number )
 669                 {
 670                         // Allocate
 671                         for( j = 0; j < Number; j++ ) {
 672                                 MM_RefPhys( PAddr + (j<<12) );
 673                                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = (PAddr + (j<<12)) | 3;
 674                         }
 675                         return HW_MAP_ADDR + (i<<12);
 676                 }
 677         }
 678         // If we don't find any, return NULL
 679         return 0;
 680 }
 681
 682 /**
 683  * \fn void MM_UnmapHWPage(Uint VAddr, Uint Number)
 684  * \brief Unmap a hardware page
 685  */
 686 void MM_UnmapHWPage(Uint VAddr, Uint Number)
 687 {
 688          int    i, j;
 689         // Sanity Check
 690         if(VAddr < HW_MAP_ADDR || VAddr-Number*0x1000 > HW_MAP_MAX)     return;
 691
 692         i = VAddr >> 12;
 693
 694         LOCK( &gilTempMappings );       // Temp and HW share a directory, so they share a lock
 695
 696         for( j = 0; j < Number; j++ )
 697         {
 698                 MM_DerefPhys( gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] );
 699                 gaPageTable[ (HW_MAP_ADDR >> 12) + i + j ] = 0;
 700         }
 701
 702         RELEASE( &gilTempMappings );
 703 }
 704
 705 // --- EXPORTS ---
 706 EXPORT(MM_GetPhysAddr);
 707 EXPORT(MM_Map);
 708 //EXPORT(MM_Unmap);
 709 EXPORT(MM_MapHWPage);
 710 EXPORT(MM_UnmapHWPage);